This invention relates generally to the processing of solids into slurries, more specifically to the processing of minerals into aqueous suspensions, and still more specifically to the processing of crude kaolin clay into an aqueous suspension.
Kaolin clay has many known applications in industry, including use as a filler in papermaking, a coating for paper, and a pigment for paint. However, crude kaolin clay ore typically contains various impurities which cause discoloration. Additionally, crude kaolin is typically too abrasive for direct use in these products. Therefore it is necessary to beneficiate the crude kaolin ore by various well-known commercial processes which increase the brightness of the kaolin particles and remove other impurities. In general, such processes for beneficiating crude kaolin clay ore require that the ore be processed as an aqueous slurry. Therefore, it is necessary as an early or initial step in so-called wet beneficiation of kaolins, to add substantial amounts of water to the dry crude kaolin clay ore to form a suspension or slurry.
Typically kaolin slurries, with solids contents less than 72% are prepared in a high shear, high energy mixing device, known to the industry as a blunger, in a process known as blunging. Crude kaolin clay ore, water and dispersing agents are simultaneously introduced into the blunger mixing chamber and subjected to strong agitation induced by a rotating blade and stationary baffle arrangement located in the lower portion of the blunger mixing chamber. In the upper portion of the mixing chamber is a series of perforated plates constructed in a cylindrical arrangement, which prevent agglomerated particles, not yet in suspension, from escaping the mixing chamber, while allowing the suspended product to overflow into a launder. The suspended product flows from the launder to a pump where it is typically pumped to degritting equipment for further processing.